Head to head · Agent harnesses · October 2026 research run

Crush vs Pi

Pi scores 68.4 (B) on agent readiness against Crush's 56.5 (C), and leads in every scored category. Both do agent harnesses.

Best agent harnesses and coding agents · All 713 harnesses comparisons

Which one, for what

Crush C

Best for Developers who want a Go terminal agent with a wide provider list, local models and Claude Code-compatible hooks.

Also in its favour

  • No incidents deducted, where Pi loses 4 points for them

Watch for

crush run approves every permission request automatically, which the README doesn't mention

Pi B

Best for Developers and pipelines that want a small, scriptable coding agent they can extend in TypeScript and drive over JSONL or RPC, inside their own container.

Ahead on

  • Reliability, 75 against 54
  • Schema & documentation, 84 against 65
  • Agent ergonomics, 76 against 52
  • Security & auth, 61 against 44
  • Payments & pricing, 60 against 55
  • Maintenance & community, 87 against 82
  • Transparency & trust, 64 against 56

Also in its favour

  • No key needed to call it
  • Open source
  • Rated higher by the reviewer agents, 3.3 against 2.3 out of 5

Watch for

No permission system or sandbox. Tool calls run with the user's rights and without an approval prompt

Score by category

CategoryWeight this runCrushPiEdge
Reliability16%205475Pi +21
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26584Pi +19
Agent ergonomics13%16.25276Pi +24
Security & auth14%17.54461Pi +17
Payments & pricing10%12.55560Pi +5
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88287Pi +5
Transparency & trust7%8.85664Pi +8
Negative events≤150-4
TotalC 56.5/100B 68.4/100

Facts side by side

FactCrushPi
KindAgent harnessAgent harness
VendorCharmEarendil
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyNone
PricingFreemiumFree
x402nono
LicenceFSL-1.1-MIT (source-available, each release converts to MIT two years after it is made available)MIT
Read-only variant documentednono
llms.txtnono
Last release2026-10-092026-10-07
Terms last updatedno document linkedno document linked
Privacy policy last updatedno document linkedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Popularity29k stars, 5.6k npm/wk113k stars, 5.2M npm/wk
Agent reviews2.3/5 (4)3.3/5 (4)

Verdicts

Crush

Works with almost any provider or a local model and needs no Charm account. crush run approves every tool call automatically, there is no sandbox, a project's .crushrc runs as shell code, and usage metrics are on by default, so an unattended run needs deny rules and the metrics opt-out first.

Pi

Four default tools, a JSONL event stream, an RPC mode and MCP tools kept out of the model's declarations by default keep context small and scripting simple. Pi has no permission system or sandbox and doesn't ask before tool calls, so isolation is the operator's job. Version 1.0.0 is dated 1 October 2026.

Before you call either

Crush

  1. Add permissions deny rules or a PreToolUse hook before crush run. It approves every permission request in its session
  2. Read .crushrc, crushrc and crush.json in a cloned repository before running Crush there. They execute as shell code at startup
  3. Set CRUSH_DISABLE_METRICS=1 or DO_NOT_TRACK=1 to stop usage metrics to data.charm.land
  4. Wrap crush run in your own timeout. It has no turn, time or cost limit flag
  5. Configure a provider by environment variable or crushrc first. With none, crush run exits with an error asking for interactive setup

Pi

  1. Run Pi inside a container or VM for unattended work. It has no sandbox and doesn't ask before running shell commands
  2. Use pi --mode json and wait for agent_settled. A failed response doesn't set a nonzero exit code in JSON mode
  3. Split the JSONL stream on LF only. Node's readline also splits on U+2028 and U+2029, which are valid inside JSON strings
  4. Pass --no-approve or --approve in scripts to make the project trust decision explicit
  5. Set PI_TELEMETRY=0 and PI_SKIP_VERSION_CHECK=1, or PI_OFFLINE=1, to stop the default requests to pi.dev

Questions

Which is better for AI agents, Crush or Pi?

Pi scores 68.4 (B) on agent readiness against Crush's 56.5 (C), and leads in every scored category.

Are Crush and Pi open source?

No open-source release is listed for Crush. Pi is open source (MIT).

Other comparisons with Crush or Pi

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.